Kepler-553
Star in the constellation Lyra
From Wikipedia, the free encyclopedia
Kepler-553 is a star in the northern constellation of Cygnus, approximately 2,430 light-years from the Solar System. It is a G-type subgiant that hosts two known exoplanets.[2][6]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h 54m 12.207s[2] |
| Declination | +48° 19′ 56.70″[2] |
| Apparent magnitude (V) | 15.15[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2] |
| Spectral type | G9[4] |
| Astrometry | |
| Radial velocity (Rv) | −27.32[4] km/s |
| Proper motion (μ) | RA: +4.607 mas/yr[2] Dec.: +28.720 mas/yr[2] |
| Parallax (π) | 1.3407±0.0189 mas[2] |
| Distance | 2,430 ± 30 ly (750 ± 10 pc) |
| Details[5] | |
| Mass | 0.889+0.046 −0.036 M☉ |
| Radius | 0.902+0.026 −0.021 R☉ |
| Luminosity | 0.536±0.041 L☉ |
| Surface gravity (log g) | 4.480+0.019 −0.027 cgs |
| Temperature | 5191+76 −78 K |
| Metallicity [Fe/H] | 0.152±0.058 dex |
| Age | 8.8+3.3 −4.0 Gyr |
| Other designations | |
| Kepler-553, KOI-433, KIC 10937029, TIC 264508613, 2MASS J19541219+4819568, LAMOST J195412.20+481956.8[3] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Planetary system
Two exoplanets are known to orbit Kepler-553, both gas giants. The inner planet, Kepler-553b, is between Neptune and Saturn in size; the outer, Kepler-553c, is a super-Jupiter in the habitable zone.[5] The planets were discovered by NASA's Kepler space telescope using the transit method, and were confirmed in 2016 by a study that used statistical validation to confirm over 1,000 Kepler candidates.[7] They were later characterized with radial velocity measurements.[5]
Kepler-553 b
Kepler-553 b is a super-Neptune-sized planet (or a sub-Saturn) orbiting close to its host star. Its mass remains unconstrained beyond an upper limit due to the challenges in detecting its weak radial velocity signal.[5]
Kepler-553 c
Kepler-553 c is a massive gas giant with a moderate orbital eccentricity, orbiting within the system's habitable zone.[5] Its equilibrium temperature of approximately 251 K[5] makes it a cold giant, potentially analogous to Jupiter but with higher metallicity.[citation needed] The planet's bulk composition is estimated to be about 8% heavy elements by mass, consistent with expectations for a gas giant of its mass.[5]
Prior to its confirmation, this planet was known as KOI-433.02,[6] and a 2011 article from the Planetary Habitability Laboratory included it in a list of exoplanet candidates that could hypothetically host potentially habitable exomoons.[8] There is as yet no evidence of any moons around this planet.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | <0.365 MJ | 0.04766+0.00081 −0.00065 |
4.0304670(18) | — | 88.94+0.67 −0.60° |
0.423+0.016 −0.011 RJ |
| c | 6.70+0.44 −0.43 MJ |
0.898+0.015 −0.012 |
328.24017+0.00039 −0.00040 |
0.346+0.020 −0.024 |
89.8314+0.0054 −0.0092° |
1.033+0.032 −0.025 RJ |